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| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2017-01-10 16:58:00 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-01-10 18:31:55 -0800 |
| commit | f073bdc51771f5a5c7a8d1191bfc3ae371d44de7 (patch) | |
| tree | 028dad6c091084d148f4b6ea4634ba31235b55bc | |
| parent | 9ebf73b275f06b114586af27cda3fd72e149d5ba (diff) | |
| download | linux-f073bdc51771f5a5c7a8d1191bfc3ae371d44de7.tar.gz linux-f073bdc51771f5a5c7a8d1191bfc3ae371d44de7.tar.bz2 linux-f073bdc51771f5a5c7a8d1191bfc3ae371d44de7.zip | |
mm: don't dereference struct page fields of invalid pages
The VM_BUG_ON() check in move_freepages() checks whether the node id of
a page matches the node id of its zone. However, it does this before
having checked whether the struct page pointer refers to a valid struct
page to begin with. This is guaranteed in most cases, but may not be
the case if CONFIG_HOLES_IN_ZONE=y.
So reorder the VM_BUG_ON() with the pfn_valid_within() check.
Link: http://lkml.kernel.org/r/1481706707-6211-2-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Cc: Robert Richter <rrichter@cavium.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/page_alloc.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 872caae544ef..74afdb4177cb 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1864,14 +1864,14 @@ int move_freepages(struct zone *zone, #endif for (page = start_page; page <= end_page;) { - /* Make sure we are not inadvertently changing nodes */ - VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page); - if (!pfn_valid_within(page_to_pfn(page))) { page++; continue; } + /* Make sure we are not inadvertently changing nodes */ + VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page); + if (!PageBuddy(page)) { page++; continue; |